Improvement in screw-drivers



S. R. KNEEL'AND.

Screw-Drivers.

No 145 506I :PatentedDemmJssL NITED STATES PATENTl orrrcn.

srLvANUs n. KNEELAND, Aor cHAnLEsTowN, MASSACHUSETTS.

IMPROVEMENT IN SCREW-DRIVERS.

Specification forming part of Letters Patent No. 145,506, dated D.cember16,1873; application ilrd November 11, 1873.

To all whom it may concern:

Be it known that I, SYLvANUs R. KNEE- LAND, of Charlestown, in thecounty of Middlesex, State of Massachusetts, have invented a certain newand useful Improvement in Screw-Drivers and I hereby declare that thefollowing is a full, clear, and exact description of the same, referencebeing had to the accompanying drawings forming a part of thisspecification, in which- Figure l is a side elevation of my improvedscrew-driver, with the casing or thimble raised. Fig. 2 is a verticalsectional view ofthe same. Fig. 3 is a transverse sectional view takenat the dotted line m, Fig. 2.

It is well known that in the use of the ordinary screw-driver itfrequently happens that it slips from the slot in the head of the screw,and does great injury to the article into which the screw is beingdriven. Sometimes this injury cannot be repaired without great cost andtrouble, especially in fine car-work, piano-work, sewing-machine work,cabinet-work, Src. The object of my invention is to prevent accidents ofthis nature and consists in providing a casing or loose thimble, soconstructed and arranged that when in use it is pushed forward ordownward by a spring over or beyond the point of the screw-driver, thusforming a socket, into which the head of the screw is inserted, wherebythe driver is prevented from slipping from the slot in the screw-headwhile the screw is being driven, said casing beging so arranged as to beraised and locked, as hereinafter described.

In Fig. 2, B is the body or shank of the screwdriver, which isconstructed hollow, or has a hole drilled longitudinally through itscenter, to a point represented by the dotted line X. In this hole acoiled spring, E, is inserted, and also a loose pin or follower, F,which follower is pressed downward by the expansive action of the springagainst the cross pin or bar d, which works in the longitudinal slot b,through the body of the shank, and is attached at each end to thethimble or casing D. At y there is a lateral slot cut at right angles tothe slot b and on the other side of the slot 1), and at the oppositeside ofthe shank B, there is a corresponding lateral slot, both of theselateral slots radiating, as it were, from the center of the shank, insuch relation to each other and to the bar as to permit the thimble D tobe rotated laterally to a certain extent when said bar is opposite ofsaid slots, the expansive action of the spring pushing or pressing thebar into slight depressions or notches in the surface of the lower shelfof the same, in such a manner as to form a bayonet or lantern lock forthe thilnble. The point or blade C of the driver is fixed in the lowerend of the shank, as shown in Fig. 2.

From the foregoing, and by reference to the drawings, it will be readilyseen and understood, by those conversant with such matters, that thethimble or guard, when in position on the shank, as shown, will bepressed downward by the action of the spring on the follower until theguard assumes the position shown by the dotted lines z z', in whichposition, if the screw-driver is used, the thimble will encircle thehead of the screw, and prevent the blade or point of the driver fromslipping from the slot in the screw-head while the screw is beingdriven.

Thenever it is desirable not to use the guard D it can be raised orpushed upwardly on the shank until the cross bar or pin arrives at thelateral slots y, when, by turning the thimble laterally, the bar el willpass from its direct path in the slot b, at a right angle, into thelateral slots y, thus keeping the thimble or guard suspended and lockedon the shank, and exposing the point C, to be used in the ordinarymanner, as also shown in Fig. 2.

I sometimes construct my improved screwdriver with a casing or thimble,as shown; but instead of having a spring, E, located in the interior ofthe shank B, I coil it around the same above the thimble, and cut alongitudinal and lateral slot through the casing, in which a pinprojecting from the shank works to form an ordinary lantern or bayonetlock. I prefer, however, the method shown and described in theaccompanying drawings and this speciication, for the reason that whenthe spring-follower and cross-bar are arranged to work within the bodyof the driver, they are protected from injury, and are not vin aposition when the driver is in use to iniiict injury upon the hand.

The follower, which iits loosely in the hole in the shank, but nearlyiills the same, prevents the spring froin crainpin g or binding, as itis liable to do Where the follower is not used7 and the spring isallowed to act directly on the cross-bar.

Like letters refer to like parts in the different figures of thedrawings.

I ani aware that a patent was granted to one Martyn, Februaryl, 1870,for an improvement in screw-drivers, in which a screw-driver isdescribed which has a cylinder or thimble sliding on the bodT of thedriver; butin his device there is no lateral slot or other provis ionfor holding or locking the thiinble at a given point, when desired7 asin mine 5 neither are the parts of his device in other importantrespects constructed or arranged like inine. I therefore do not hereinclaim anything Whatsoever shown or described in said patent, when in andof itself considered; but

That I do claim is- The screw-driver described, consisting of thevarious instrunientalities shown, constructed, arranged, and usedsubstantially as and for the purpose set forth and specified.

SYLVANUS R. KNEELAND. fitnesses E. P. BOARDMAN, Gillis. Ln'r'rs.

